12-2.c

提供了许多线程间通信的实例程序。用linux下的C语言实现。

#ifdef __Linux__
 #  define _REENTRANT
#  define _POSIX_SOURCE
#endif
 
 /* Hack for LinuxThreads */
 #ifdef __Linux__
 #  define _P __P
 #endif
 
 #include <pthread.h>
 
 #include <string.h>	/* for strerror() */
 
 #include <stdio.h>
 
 #define NTHREADS 4
 
 #define errexit(code,str)                          \
   fprintf(stderr,"%s: %s\n",(str),strerror(code)); \
   exit(1);
 
 /******** this is the thread code */
 void *hola(void * arg)
 {
   int myid=*(int *) arg;
 
   printf("Hello, world, I'm %d\n",myid);
   return arg;
 }
 
 /******** this is the main thread's code */
 int main(int argc,char *argv[])
 {
   int worker;
   pthread_t threads[NTHREADS];                /* holds thread info */
   int ids[NTHREADS];                          /* holds thread args */
   int errcode;                                /* holds pthread error code */
   int *status;                                /* holds return code */
 
   /* create the threads */
   for (worker=0; worker<NTHREADS; worker++) {
     ids[worker]=worker;
     if (errcode=pthread_create(&threads[worker],/* thread struct             */
 		       NULL,                    /* default thread attributes */
 		       hola,                    /* start routine             */
 		       &ids[worker])) {         /* arg to routine            */
      errexit(errcode,"pthread_create");
    }
   }
   /* reap the threads as they exit */
   for (worker=0; worker<NTHREADS; worker++) {
     /* wait for thread to terminate */
     if (errcode=pthread_join(threads[worker],(void *) &status)) { 
      errexit(errcode,"pthread_join");
    }
     /* check thread's exit status and release its resources */
     if (*status != worker) {
       fprintf(stderr,"thread %d terminated abnormally\n",worker);
       exit(1);
    }
   }
   return(0);
 }